The present invention relates to lighted footwear and, more particularly, to footwear with light modules that apply power from a power source in such a way as to turn on the lights so the safety of the wearer is improved, the useful life of the power source is extended and an attractive lighting pattern is created.
At various times in the past, lighted footwear has enjoyed some popularity. This lighted footwear all has the same basic components, i.e., at least one light source, a source of power for the light or lights and a switch of some sort to apply the output of the power source to the light to cause it to come on and provide illumination. The lights can be of a variety of types, e.g., incandescent bulbs, electroluminescent panels, and light emitting diodes (LEDs). These are popular lights for this purpose because they can be lighted by the power from small batteries, so that the elements lighting the light can be encapsulated in the footwear and need not be connected to any external power source. However, there is no reason that light sources which require a.c. voltage or current, such as fluorescent lights, could not be used in lighted footwear, assuming a suitable power source were provided. Consequently, as used in this application, "light source" is intended to encompass any device capable of generating detectible light, visible or otherwise, e.g., infrared.
In its simplest form lighted footwear typically has lights in the heel and along the sole of the footwear, which could be athletic, casual shoes, formal shoes or sandals for men, women or children. A battery, e.g, of three (3) volts output, is incorporated in the heel or sole of the shoe and is connected by wires to the lights. A switch is provided in the connecting wires to control the illumination of the lights, which switch may be a simple manual switch as disclosed in U.S. Pat. No. 4,158,922 of Dana, III. Thus, whenever the user wishes the lights to be on, for example, just before he or she goes jogging at night, he or she can turn on the lights by operating the switch. However, with such an arrangement the lights would be on continuously until the switch is turned off.
If the lights are flashed intermittently, there are two advantages. First, the life of the battery is increased in proportion to the time the lights are off during the intermittent flashing. Second, a more attractive eye-catching display is provided. When running at night, the flashing of the lights makes the user more visible, e.g., to motorist, so that the safety of the user is increased. One way to achieve a flashing effect is to utilize a motion-activated switch to apply power to the lights. This could be a mercury switch which is in the form of a tube containing a quantity of mercury and having spaced-apart electrical contacts. The tube is oriented on the footwear so that when the footwear is flat, there is no connection between the contacts. However, as the footwear is tilted, as during the taking of a step, the mercury runs down the tube and closes the contacts. This contact is broken again when the footwear is flat again at the completion of the step. Thus, as the user walks, the lights come on and go off. Mercury switch operated lighted footwear is disclosed in U.S. Pat. No. 4,848,009 of Rodgers and the Dana III '922 patent mentioned above.
In another form of motion-activated switch, the mercury in a mercury switch is replaced for environmental reasons with a metal ball that rolls in the tube. Further, mechanical motion activation can be achieved by the mechanical lever system disclosed in U.S. Pat. No. 2,572,760 of Rikelman. In addition, intermittent operation of the lights can be achieved by a pressure switch. During jogging, whenever the wearer's foot hits the ground the pressure activates a switch in the shoe which closes the circuit and causes the lights to flash. Such a pressure switch is disclosed in European Patent Application No. 0 121 026 of Dana III.
Another way to achieve an intermittent lighting effect is to incorporate an electronic circuit into the flashing footwear. This circuit could be an integrated circuit low frequency oscillator or flasher operated by the switch and providing the power to the lights. Whenever the switch is closed the oscillator provides power to the lights at a slow rate, e.g., from 0.5 to 2.5 Hz. Such a flasher could be like the National Semiconductor LM3909 LED Flasher/Oscillator. Use of this device to provide intermittent lighting is disclosed in the Dana III European patent application. The U.S. Pat. No. 4,158,922 of Dana III also discloses a low frequency oscillator made from individual components which is used in this fashion.
One problem with these prior motion-activated switches, e.g., the mercury, ball, lever and pressure switches, is that they can remain continuously closed, thus allowing the lights to stay on and running the battery down. For example, if shoes with the mercury, ball or lever switches are placed at an attitude corresponding to a step in walking, the switch will close and the lights will light continuously. Similarly, the shoes with the pressure switch can be packed so there is enough pressure on the switch so that these lights are on. If this happens in transit from the factory to the store shelves, the flashing effect may no longer work at the time an attempt is made to sell the product to the ultimate user or soon after the sale. This can cause customer complaints and returns of the merchandise. With the pressure switch, if the wear is merely standing in one place for too long, the lights will remain on and premature exhaustion of the battery will occur.
An electronic solution to the problem of premature battery exhaustion is disclosed in U.S. Pat. No. 4,848,009 of Rodgers. The Rodgers patent proposes that the power to light the lights be provided from the battery through a circuit. This circuit is than controlled by the switch and a further timing circuit so that when the switch closes the circuit provides power to the light and starts the timing circuit. After a predetermined period of time the timing circuit signals the power circuit to cut off the power to the lights. Power cannot be reapplied to the lights until the switch opens and closes again. This results in a single illumination of the lights for a fixed period of time in response to the closure of the switch.
An alternative arrangement for avoiding premature battery exhaustion is provided in U.S. Pat. No. 5,408,764 of Wut. The Wut arrangement uses a battery, lights and a spring switch. The spring switch is in the form of a coil of spring wire which is cantilevered over an electrical contact on a printed circuit board. The other end is also connected to an electrical contact. Whenever a jolt is given to the switch, a module containing the switch, or a shoe containing the switch, the coil of wire will swing into contact with the printed circuit board contact, thus closing the circuit and supplying power to light the lights. However, because of the spring nature of the coil, it swings back out of contact with the printed circuit board as soon as the momentum applied by the jolt is overcome. As a result the spring switch provides only intermittent contact, so it cannot apply power to the lights for a long period of time and run down the battery.
It is known to provide enhanced attractiveness to flashing footwear by providing sequential lighting of a plurality of lights instead of mere intermittent lighting. Thus, for example, if there were three lights on the shoe, each switch closure would cause them to light in sequence, as opposed to simultaneously, and the sequence could be repeated two or more times.
The Rodgers and Wut patent designs provide single illuminations of the lights when the foot hits the ground during walking or jogging. This is the position during walking or jogging when the feet are least visible. For example if the wearer is jogging in grass of even moderate height, the lights may be obscured by the grass, thus making the wearer less visible and more susceptible to danger. Thus, it would be beneficial to have lighted footwear that could provide lighting in a unique and novel sequence while the foot is raised, but still avoid the problem of premature battery exhaustion.